The objective of the study is to compare carcinoma of the prostate gland in a high-risk (American blacks) and a low-risk (African blacks) population group. Specifically, the study will (1) compare the clinical features, plasma hormone (testosterone, estrone and estradiol) levels, epidemiologic factors and tumor morphology of patients with invasive carcinoma of the prostate in the two groups, (2) determine in post-mortem material the incidence of incidental (non-invasive) carcinoma of the prostate in the specified population groups and (3) study the relation between incidental carcinoma and non-neoplastic prostatic changes and morphologic changes in liver, adrenal glands, breast and testes. The clinical features of patients with prostatic carcinoma will be evaluated by established clinical methods and the disease will be staged. Plasma steroid hormone levels will be determined by radioimmunoassay methods. Epidemiologic data, utilizing a retrospective approach, will be collected by a pre-tested questionnaire. Hormone levels and epidemiologic data will be collected from matched, non-urologic, non-endocrinologic hospital control patients. Sections of prostate glands from patients with invasive carcinoma will be evaluated morphologically and correlated with clinical features and stage, hormone levels and epidemiologic data. Whole prostate glands with attached seminal vesicles together with blocks of liver, breast, adrenal glands and testes from necropsy cases in the two population groups will be analyzed for morphologic changes according to a specific protocol.